Wiring device



Sept. 19, 1961 c.-M. SMITH 3,001,168

WIRING DEVICE Filed OGt. 2l. 195'? 2 Sheets-Sheet 1 27 Y @jr ll Sept.19, 1961 c. M. SMITH 3,001,168

WIRING DEVICE Filed oct. 21. 195? 2 Sheets-Sheet 2 6l Fi g. 9.

WITNESSESt |NVENTOR @MMSI G- Clarence M. Smh

ATTORNEY atei 3,0@Ll63 Patented Sept. 19, 1961 Conn., assigner to TheBridgeport, Conn., a corpo- This invention relates generally to electricwiring de'- vices, and more particularly to wall outlets for use withplug connectors to connect various fixtures to a house circuit.

yln the past unitary contact and terminal members have been provided forelectric wiring devices wherein the terminal portion thereof is of thescrewless terminal type and the contact portion is adapted to receivethe prongs of a male electrical plug. A problem has been encountered forunitary terminal and contact structures of this type particularly wherethe terminal portion is provided with a pair of spaced wire grips whichare formed by slotting the terminal portion longitudinally and wherefemale contacts are located to extend laterally from opposite ends ofthe wire grips. In these constructions the female contact comprises apair of spaced portions ex* tending laterally from each end of the wiregrips. T he aforementioned problem arises when a lead wire is insertedinto the slot to enga-ge the wire grips or when a male prong engages thefemale contact. The insertion rof the lead wire causes the grips to moveupwardly in the direction of insertion of the lead wire and outwardlytoward its side edges. The stresses formed in the member by theaforementioned motion of the wire grip is transmitted to the femalecontact portions and causes them to spread further apart, whereby thecontact pressure exerted on the male prongs is decreased, and anundesirable and ineflicient connection between the wiring device and themale plug is created. Similarly, the engagement of the female contactwith a male prong causes the female contact portions to be spread apart,which motion is transmitted to the wire grips to weaken the connectionbetween the wire grips and a lead wire. The prior art `structures haveattempted -to reduce this adverse effect by making slight enlargementsof the slot adjacent the ends of the wire grips, but the resultingstructure has not been successful.

The present invention is specifically directed toward the elimination ofthe aforesaid problem by providing means on the unitary structure forlocalizing stresses built up in the wire gripping portions and the prongengaging portions thereof. A unitary female contact is substituted forthe pair of spaced portions provided in the prior art. The unitaryfemale contact is preferably U-shaped and has one of its side edgesconnected to the end of the unitary structure through a rigid transitionmember. Thus, a male prong is engaged by the spaced arms of the U-shapedfemale contact and any stresses built up in the arms are absorbed inmovement of the arms relative to each other and in the rigid supportingstructure of the female contact. Located between the wire grips and therigid support structure are sections greatly reduced in area so thatupon stressing of the wire grip by a lead wire, the stresses built upare absorbed by the reduced area sections and are not transmitted to thefemale contacts.

An object of the invention is to provide an improved electric outlet ofsimplified construction.

Another object of this invention is to provide an electrical device towhich a wire may be easily and quickly attached.

Another object of this invention is to provide an improved unitaryconnector structure for a wire device having spaced wire gripping andcontact engaging portions and formed so that stresses built up in one ofthese portions is not transmitted to the other.

Still another object of this invention is to provide an improvedconnector structure for a wire device having means for limiting themovement of wire gripping means formed thereon which move in response tothe insertion of a lead wire.

Another object of this invention is to provide an irnproved connectorstructure for wiring devices in which the wires are connected to thewiring device and locked in place with good electrical connections byinserting the stripped end of the wire through an opening in the housingof the device.

The invention both as to structure and operation, together withadditional objects and advantages thereof, will be best understood fromthe following detailed de scription of several embodiments thereof, whenread in conjunction with the accompanying drawings.

In said drawings:

FIGURE l is a front elevation of a receptacle embodying the principlesof the invention;

FIG. 2 is a front elevational view of the receptacle shown in IFIG. lwith cover removed;

FIG. 3 is a plan view of one of the connecting strips with the integralcontacts;

FIG. 4 is a side elevational View of strip shown in FIG. 3;

FIG. 5 is a sectional view taken on line V-V of FIG. l and looking inthe direction of the arrows;

FIG. 6 is a rear elevational view of the receptacle shown in FIG. lshowing the wire receiving hol-es and release openings through which atool is inserted to release the Wires;

FIG. 7 is a sectional view taken on line Vil-VII of FIG. 6 and lookingin the direction of the arrows;

FIG. 8 is a perspective view showing a side wiring device for use with amodified conducting strip similar to that shown in FIGS. 3 and 4; and

FIG. 9 is a transverse sectional view of the device shown in FIG. 8assembled in a receptacle.

Referring to the drawings, the receptacle comprises an upper housing 11and a lower housing V13, both of molded insulating material, a pair ofelongated electrical contact members or terminals 15 and a yoke 17 formounting the receptacle in a suitable outlet box. Referring to FIGS. l,5 and 7, the upper housing portion 11 is an irregularly formed memberhaving irregularly formed, downwardly extending, laterally spaced sideportions 19 and a pair of longitudinally spaced faces 21 substantiallyoval in shape and having spaced slots 23 therein for receiving theprongs of a male plug.

The lower housing 13 comprises a substantially rectangular base havingupwardly extending side walls 25 and end walls 27. The lower edges ofthe side walls 19 of the upper housing 11 are adapted to engage the sidewalls 25 of the base when the receptacle is assembled. The two parts ofthe housing are secured together by means of screws 29 (-FIG. 6) whichpass upwardly through the bottom portion or base 13, through openings(not shown) in the yoke 17 and are threaded into openings in the upperportion 11 of the housing. A centra-l opening 31 (FIG. l) in the upperportion 11 of the housing and a threaded opening in the yoke 17 `areprovided for the purpose of attaching a ush cover plate to thereceptacle.

The base 13 is longitudinally divided into two symmetrical spaces orcompartments 33 by a pair of central longitudinally spaced ribs 35. Eachof the compartments are provided with surfaces and projections forreceiving and retaining a conductive connecting or contact member yasshown in FIGS. 3, 4 and 8. Each side wall 25 of the base 13 is providedwith longitudinally spaced ribs or projections 37 for locating thecontact members 15 the conducting lengthwise in the base. Extendingtransversely across the bottom portion of the base adjacent the ribs 37are ribs 39 upon which the contact portions of the connecting member l5rest when placed in position. The upper housing ll (FIGS. 5 and 7) isprovided with downwardly extending projections 41 spaced on oppositesides of the transverse center base of the receptacle with a transversespace 43 therebetween. A spacer 45 disposed transversely of the baseinthe space 43 has downwardly extending prongs 47 (FIGS. 7 and 9) forengaging the edges of the termina-ls or connecting members l5 to holdthem in place. As seen in FIGS. 2 and 9, the ends of the spacer 45engage in vertical slots 49 in the side walls 25 of the base. As seen inFIGS. 7 and 9, the spacer 45 is held in place by the upper housingmember ll `and by the yoke I7 when the receptacle is assembled.

When the connecting or contact members l5 (FiG. 2) are assembled in thebase 13, they `are accurately located and held in position by the ribs37, 139 and 35, by the side walls 25 of the base i3, the spacer 45 andby the upper housing member 1l without being positively attached to thehousing. FIGS. 3 and 4 illustrate a contact member 15a which isgenerally the same as the contact member 15 shown in FIGS. 2, 5 and 8with the exception that the contact blades at the ends thereof extendtransversely of themain body of the contact member whereas the contactblades of the members 15 (FIG. 8) extend longitudinally of the contactmember. By assembling the contact members 15 (FIG. 2) in the base 13male plugs havingtheir prongs spaced laterally may be inserted throughthe housing slots 23 (FIG. l). If the contact members 15a (FIGS. 3 and4) are assembled in theV receptacle, male plugs having their prongsspaced edgewiise may be inserted in the slots 23.

Referring to FIGS. 2 and 8, the terminal members l5 are formed from aflat strip of resilient conductive material, such as brass or copper, byany suitable mechanical process, such as stamping. When so formed, eachelongated contact member 15 hasan upwardly extending portion 5l at eachend thereof from which spaced contact l lades 53 extend longitudinallyoutward and are disposed beneath the housing slots 23 to be engaged bythe prongs of an inserted connector plug. Openings 57 are formed in `themain body of the contact member l5 adjacent to but spaced from theupaturned portions 51 and a slot 59 extends between the openings 57along the longitudinal center line of the contact member 15 to form wiregripping or spring locking tongues 6l. The spring locking tongues 61`are formed upwardly at opposing angles (FIG 7) and in their assembledpositions rest on inclined surfaces 63 on the base 13; Recesses 65 areformed in the outer edges of the gripping or locking portions 6i to per--rnit twisting at these points and thus prevent torsion stresses frombeing transferred to the base 51 of the female contact blades 53.v

In order to connect `a lead wire or a conductor to the Contact membersl5, it is necessary merely to insert the stripped end of a wire into anopening 67 in the lower housing i3 (FIGS. 5, 6 land 7). When thusinserted, the end 69 of the wire engages between the gripping edges ofthe gripping or locking portions 6l and separates them to be held firmlyin the slot 59 and to make a good electrical connectionV with thecontact member l5. Obviously, any y'attempt to withdraw such an insertedwire results in the gripping edges of the locking portions 6l morefirmly engaging the wire.

When -a plug is inserted into the contact blades 53 in a twisted orslanted manner, the blades 53 can respond to the twisting or distortingeffect by deiecting about portions indicated by the reference character71 (FGS. 2 and S) or by twisting about the narrowportions adjacent theopenings 57 without disturbing the spring locking tongues 6l yand thusmaintain good gripping tension Ilon the lockingV tongues-6l.y By thesame token, the locking portions-61,1,when deflected `,by lan insertedwire by a twist- 4 ing action localized at recesses 65, do not alfectthe blades 53.

As previously stated, the contact member `15a shown in FIGS. 3 and 4,except for the arrangement of the female contacts 53a at the endsthereof, is the same as the contact i5. The contact` blades 53a aresupported on base portions 51a `and extend transversely of thelongitudinal.

center line of the termina-l 15e instead of longitudinally thereof as inFIGS. 2 and 8.

FIGS. 8 and 9 illustrate an adapter as well as a modified base i3dwhereby a receptacle provided with the contact mem-bers l5 is connectedfor side wiring. Terminal piates 73 provided with connecting screws 75are disposed one against each of the opposite sides of the base 13a.Formed integral with the terminal plate 73 and at right angles theretois a conductive strap '77 which extends through the base 13a and whichhas an upwardly turned portion at the inner end thereof which isinserted between the spring locking tongues 61 0f the terminal 15 asshown in FIGS. 8 and 9. The openings in the base 13a through which thestraps 77 extend are slightly wider than the straps 77 and a piece ofinsulating material 81 is suitably provided on the base 13a to minimizeexposure of the straps 77. n

As shown in FIGS. 5, 6 and 7, access openings 83 are provided in thebottom of the base 13 through which a tool, such as a screw device, canbe inserted between the spring locking tongues 61 and, by a slighttwist, force the tongues 6l apart to release the Wire 49.

The invention provides a pair of easily formed terminals which may beinserted into and properly located within the receptacle without the useof tools and which is held in position without being positively fastenedto the receptacle housing. When assembled in the receptacle the terminalis readily connected to an electrical conductor by merely inserting theconductor through a suitable opening in the bottom of the receptacle andforcing the bared end thereof between the spring locking tongues so thatit is gripped by the tongues. It will be further noted that the springlocking tongues are free of any distortion or twisting of the femalecontacts upon the improperinsertion of the prongs of a male plug, andthe contacts are unaffected by deection of the wire locking tongues.

While the invention has been disclosed in accordance with the provisionsof the patent statutes, it is-to be understood that various changes andmodifications in the structural details thereof may be made withoutdeparting from the spirit of the invention.

l claim as my invention:

l. A wiring device comprising a hollow casing of insulating material7 anelongated terminal member disposed in fixed relationship within saidcasing, a pair of spring locking tongues formed longitudinally on saidterminal member and spaced apart to engage iirmly a conductor insertedtherebetween, a terminal plate having a wire engaging portion positionedoutside said casing and having another portion extending Ythrough apassage in said casing, said other terminal portion having its inner endrmly engaged by said locking tongues on said terminal member, and meansfor precluding detlecting forces on said tongues from elfecting theremainder of said terminal.

2. A wiring device comprising a hollow casing of insulating material, anelongated terminal member disposed in fixed relationship within saidcasing, a pair of spring locking tongues formed longitudinally on saidterminal member and spaced apart to engage firmly a conductor insertedtherebetween, a pair of contact blades formed on each end of saidterminal member, a terminal plate having one portion positioned outsidesaid casing and having another portion extending into said casing, saidother plate portion having its inner end rmly engaged by said lockingtongmes on said terminal member.

3. A wiring device comprising a hollowV casing of insulating material,an elongated terminal member disposed in fixed relationship within saidcasing, a pair of spring locking tongues formed longitudinally on saidterminal member and spaced apart to engage rmly conductor insertedtherebetween, a pair of contact blades yformed on each end of saidterminal member, portions on said terminal member located between saidcontact blades and said spring locking tongues being reduced incross-sectional area to prevent stresses on said contact blades frombeing transmitted to said spring locking tongues by enabling said bladesand said tongues to be deliected about said portions, respectively, aterminal plate having one portion positioned outside said casing andhaving another portion extending into said casing, said other plateportion having its inner end firmly engaged by said locking tongues onsaid terminal member.

4. A wiring device comprising a hollow casing of insulating material, anelongated terminal member disposed in iixed relationship within saidcasing, a pair of spring locking tongues formed longitudinally on saidterminal member and spaced apart to engage firmly a conductor` insertedtherebetween, a terminal plate having at least a portion thereof exposedto the exterior of said casing and having another portion firmly engagedby said locking tongues on said terminal member.

5. A wiring device comprising an elongated casing of insulatingmaterial, an elongated `generally rectangular and resilient terminalbeing supported within said casing, a face side of said terminalextending longitudinally adjacent a back side of said casing, saidterminal including a pair of conductor engaging tongues extending in thelongitudinal direction and having opposed clamping edges extending thelength thereof and being faced to engage conductors inserted throughsaid casing back side, said terminal also including a prong engagingcontact projecting from each of opposite ends of said terminal into saidcasing, a portion of said terminal intermediate said tongues and each ofsaid contacts having an opening so that said terminal portion is reducedin lateral cross-section, and each of said tongues having a notch spacedlongitudinally inwardly of each of said openings and extending inwardlyfrom respective outer edges laterally opposite said clamping edges, theinward extent of said notches being suilicient to enable each of saidtongues to pivot about a substantially longitudinal reference lineextending through its notches and said openings, whereby the etect ofbending moments on said tongues is localized.

6. A wiring device comprising an elongated casing of insulatingmaterial, an elongated generally rectangular and resilient terminalbeing supported Within said casing, a face side of said terminalextending longitudinally adjacent a back side of said casing, saidterminal including a pair of conductor engaging tongues extending in thelongitudinal direction and having opposed clamping edges extendingsubstantially the length thereof and being faced to engage conductorsinserted through said casing back side, said terminal also including anintegral U-shaped Contact projecting from each of opposite ends of saidterminal into said casing, one of a bight portion and an arm of each ofsaid contacts being deflectable about respective lateral reference linesthrough said terminal, a portion of said terminal intermediate saidtongues and each of said contacts having an opening so that saidterminal portion is reduced in lateral cross-section, and each of saidtongues having a notch spaced longitudinally inwardly of each of saidopenings and extending inwardly from respective outer edges laterallyopposite said clamping edges, the inward extent of said notches beingsuicient to enable each of said tongues to pivot about a substantiallylongitudinal reference line extending through its notches and saidopenings, whereby the eiect of bending moments on said tongues islocalized.

References Cited in the tile of this patent UNITED STATES PATENTS1,582,957 Avery May 4, 1926 1,719,363 Gaynor July 2, 1929 1,977,487 NeroOct. 16, 1934 1,986,652 Wack Ian. l, 1935 `2,228,683 Barrelle Jan. 14,1941 2,396,725 Thomas Mar. 19, 1946 2,649,558 Franz Aug. 18, 19532,698,423 Modrey Dec. 28, 1954 2,748,363 Despard May 29, 1956 `2,773,248Smith Dec. 4, 1956 2,873,433 Despard Feb. 10, 1959 2,875,424 HubbellFeb. 24, 1959 2,890,436 Bentley June 9, 1959

